查看更多>>摘要：Supply chain management is an increasingly important organizational concern, and proper evaluation of suppliers constitutes one essential element of supply chain success. Continuous evaluation of a particular supplier becomes more important considering the fact that in most industries the cost of raw materials and component parts constitutes the main cost of a product, such that in some cases it can account for up to 70%. However, there is little research that has helped the organizations in continuous evaluation of their suppliers. We propose a new model, based on fuzzy logic to handle the various attributes, associated with supplier evaluation problems. Four multi-input single output (MISO) mamdani fuzzy inference systems have been proposed for supplier evaluation. The proposed model has also been illustrated through a case study.
查看更多>>摘要：In this paper, we consider a nonlinear system of Volterra integral equations, and apply Newton's method to linearize it. We solve each step of Newton's system by the product integration technique. Also, we provide the sufficient conditions for convergence of the numerical method. Finally, we give a test problem to illustrate the applicability and accuracy of the presented method.
查看更多>>摘要：In this paper, an analytical solution for boundary layer flow over a flat plate with slip flow and constant heat flux surface condition has been presented for the first time. The Navier-Stokes and energy equations are reduced by a similarity transform in order for a set of nonlinear ordinary differential equations to be formed. Then, governing equations will be solved analytically by using a kind of analytic technique for nonlinear problems which has been named the homotopy analysis method (HAM). The obtained results of this study have been compared with the results of differential quadrature method (DQM) as a promising numerical method. Very good agreement has been shown between analytical results and those obtained by DQ. Finally, effects of the Prandtl number and rarefaction parameter K on velocity and temperature profiles are investigated.
查看更多>>摘要：This paper which is based on neighboring optimal control investigates the application of an analytical feedback guidance scheme for the problems of low-thrust orbital transfer. Neighboring optimal control is one of the methods that has been proposed for the closed-loop optimal guidance. This method focuses on expanding the cost function to second order and examining the robustness of the system by the feedback law gains. At first, the open-loop analytical guidance policy is considered as the optimal thrust steering program that will transfer the vehicle from the inclined low earth orbits to the high earth orbits. Secondly, proper feedback optimal guidance laws are analytically obtained to maintain the trajectories around their optimum with assessed disturbances. The proposed guidance scheme is distinguished for two desired performance indices as minimum-time and minimum-effort. Finally performance indices are compared and the best policy is obtained regarding the robustness of the two performance indices against disturbances.
查看更多>>摘要：We present a wavelet based multiresolution method coupled with smooth fictitious domain and wavelet-vaguelette method to solve the one-dimensional elliptic problem equipped with Dirichlet boundary condition. Its advantages over the classical fictitious domain method are analyzed by interior error estimate and numerical examples. The efficiency of our method is pointed out by considering a Stefan problem with exact solution in one dimension.
Talaat S. El-DanafMohamed A. RamadanAhmed M. E. Bayoumi
17页
查看更多>>摘要：In this paper, we consider two iterative algorithms for the Sylvester-conjugate matrix equation AV + BW = EVF + C and AV + BW = EVF + C. When these two matrix equations are consistent, for any initial matrices the solutions can be obtained within finite iterative steps in the absence of round off errors. Some lemmas and theorems are stated and proved where the iterative solutions are obtained. Two numerical examples are given to illustrate the effectiveness of the proposed method.
查看更多>>摘要：This paper proposes a new complex-valued wavelet network based on Gabor transfer functions which have complex-valued weights, input/output variables and translation parameters. A learning algorithm is developed by using the technique of genetic algorithm to facilitate implementation of the network. The effectiveness of the proposed network is evaluated by applying the network to approximate several complicated nonlinear functions, and to tackle the 4-QAM (quadrature amplitude modulation) digital communications channel equalization and the image enhancement via feature extraction problems in signal processing. Indeed, the evaluation results obtained by testing the proposed wavelet network with real facial and textile fabric images clearly show that it is a very useful tool for solving problems in the field of complex-valued signal analysis.
查看更多>>摘要：An m-point boundary value problem with one-dimensional p-Laplacian at resonance on [0, ∞) is considered. By establishing a continuation theorem and applying a suitable homotopy, Leray-Schauder degree, a priori estimate, the existence of solutions to the above problem is obtained.
查看更多>>摘要：In this paper, we will employ some dynamic inequalities of Opial's type on time scales to prove several results related to the spacing between consecutive zeros of a solution of a second order dynamic equation with a damping term. We also obtain several results related to the spacing between a zero of the solution and/or a zero of its derivative. As a special case, we will establish some new results for differential and difference equations with damping terms. For illustration, we will derive some well-known results obtained for differential equations without damping terms. The results yield conditions for disfocality and disconjugacy for dynamic equations with damping terms on time scales.
查看更多>>摘要：This study develops a series of models to determine aircraft types and flight frequencies on individual routes, and evaluate the reliability of proposed network planning during fluctuations in jet fuel prices. The reliability of individual routes is evaluated as to whether revenues from flights with initially proposed flight frequencies and aircraft types can accommodate variations in jet fuel expenditures. We define reliability as the probability that the proposed flight frequencies will operate in at least a break-even condition under future fuel price fluctuations. A case study is provided using an international airline in Taiwan to evaluate its network reliability in response to jet fuel price fluctuations in 2008. The results indicate that not only do routes with low load factors show low reliability, but long distance routes with high load factors also show low reliability during periods with high fuel prices. The results of the study provide effective ways to enhance commercial airline network designs in response to the uncertainty of jet fuel prices.
NSTL
Elsevier